clang/lib/AST/Interp/InterpState.cpp

   1 //===--- InterpState.cpp - Interpreter for the constexpr VM -----*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "InterpState.h"
  10 #include "InterpFrame.h"
  11 #include "InterpStack.h"
  12 #include "Program.h"
  13 #include "State.h"
  14
  15 using namespace clang;
  16 using namespace clang::interp;
  17
  18 InterpState::InterpState(State &Parent, Program &P, InterpStack &Stk,
  19                          Context &Ctx, SourceMapper *M)
  20     : Parent(Parent), M(M), P(P), Stk(Stk), Ctx(Ctx), Current(nullptr) {}
  21
  22 InterpState::~InterpState() {
  23   while (Current) {
  24     InterpFrame *Next = Current->Caller;
  25     delete Current;
  26     Current = Next;
  27   }
  28
  29   while (DeadBlocks) {
  30     DeadBlock *Next = DeadBlocks->Next;
  31     std::free(DeadBlocks);
  32     DeadBlocks = Next;
  33   }
  34 }
  35
  36 Frame *InterpState::getCurrentFrame() {
  37   if (Current && Current->Caller)
  38     return Current;
  39   return Parent.getCurrentFrame();
  40 }
  41
  42 bool InterpState::reportOverflow(const Expr *E, const llvm::APSInt &Value) {
  43   QualType Type = E->getType();
  44   CCEDiag(E, diag::note_constexpr_overflow) << Value << Type;
  45   return noteUndefinedBehavior();
  46 }
  47
  48 void InterpState::deallocate(Block *B) {
  49   assert(B);
  50   const Descriptor *Desc = B->getDescriptor();
  51   assert(Desc);
  52
  53   if (B->hasPointers()) {
  54     size_t Size = B->getSize();
  55
  56     // Allocate a new block, transferring over pointers.
  57     char *Memory =
  58         reinterpret_cast<char *>(std::malloc(sizeof(DeadBlock) + Size));
  59     auto *D = new (Memory) DeadBlock(DeadBlocks, B);
  60
  61     // Move data and metadata from the old block to the new (dead)block.
  62     if (Desc->MoveFn) {
  63       Desc->MoveFn(B, B->data(), D->data(), Desc);
  64       if (Desc->getMetadataSize() > 0)
  65         std::memcpy(D->rawData(), B->rawData(), Desc->getMetadataSize());
  66     }
  67
  68     // We moved the contents over to the DeadBlock.
  69     B->IsInitialized = false;
  70   } else {
  71     B->invokeDtor();
  72   }
  73 }